JPH11248294A - Refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the burden of power side and improve the coefficient of performance as well as improve the cooling performance without giving a large change to the conventional refrigerating machine. SOLUTION: A low-temperature low-pressure refrigerant which passes through a compressor 11, a condenser 12, a liquid receiver 13, an expansion valve 14, and an evaporator 15 in this order, is heat-exchanged with a high-temperature high-pressure refrigerant in the liquid receiver 13, and the low-temperature low-pressure refrigerant are returned to the compressor 11. A heat exchanging means 17 having such a function is provided within the liquid receiver 13. A temperature sensor 16 is provided between the liquid receiver 13 and compressor 11, and it detects the temperature of a refrigerant which is heat-exchanged in the liquid receiver 13 and returns to the compressor 11 and controls an opening of the expansion valve 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigeration system.

[0002]

2. Description of the Related Art Conventionally, as a refrigerating apparatus, there has been known a refrigerating apparatus in which a refrigerant which has passed through a compressor, a condenser, a liquid receiver, an expansion valve and an evaporator in this order returns to the compressor. .

FIG. 5 shows an enthalpy pressure curve of a cycle of compression, condensation, expansion and evaporation in a conventional refrigeration system.
Shown in In the figure, the part indicated by B'-B is the last part in the condenser, and functions as a supercooling unit for cooling the liquid-phase refrigerant to a temperature below the saturation temperature. The part shown is the last part in the evaporator and functions as a superheater for heating the gas-phase refrigerant to the saturation temperature or higher.

[0004]

In the above-mentioned conventional refrigeration system, there is a problem that the cooling performance is sacrificed because the evaporator is provided with a superheated portion. However, there has been a problem that the area of the condensing section is substantially reduced, and the load on the power side is increased due to an increase in the condensing pressure.

[0005] In order to solve the above-mentioned problem of the condenser, the refrigerating apparatus which provides the supercooling section is required to connect the condenser and the liquid receiver and supply the condensed liquid in the liquid receiver to the supercooling section. However, the whole apparatus is complicated, and a practically sufficient one has not been obtained.

An object of the present invention is to provide a refrigeration apparatus which can improve the cooling performance, reduce the load on the power side, and improve the coefficient of performance without making significant changes to the conventional refrigeration apparatus. It is in.

[0007]

A refrigerating apparatus according to the present invention is a refrigerating apparatus having a compressor, a condenser, a liquid receiver, an expansion valve, and an evaporator.
Heat exchange means for exchanging heat between the low-temperature low-pressure refrigerant passing through the expansion valve and the evaporator and the high-temperature high-pressure refrigerant in the receiver and returning the low-temperature low-pressure refrigerant to the compressor is provided in the receiver. It is characterized by the following.

[0008] The heat exchange means in the liquid receiver comprises, for example, a helical heat exchange tube provided at a lower portion in the liquid receiver, and the inlet of the heat exchange tube and the outlet of the evaporator have a low temperature. The outlet of the heat exchange tube and the inlet of the compressor are connected by a low-temperature and low-pressure refrigerant discharge tube. The heat exchange means may be constituted by a single pipe, a plurality of pipe groups, or a heat exchange chamber may be provided in the liquid receiver. Of course, the shape of the heat exchange tube can be variously changed.

According to the refrigerating apparatus of the present invention, the heat exchange in the receiver causes the low-temperature low-pressure refrigerant, which is almost or entirely in the gas phase, to pass through the evaporator, and almost or all to pass through the condenser. Exchanges heat with the high-temperature, high-pressure refrigerant in the liquid phase, the low-temperature, low-pressure refrigerant is heated to a superheated gas-phase refrigerant, and the high-temperature, high-pressure refrigerant is cooled to a supercooled liquid-phase refrigerant. Therefore, it is not necessary to provide the superheater of the evaporator and the supercooler of the condenser, which are conventionally required.

[0010] Further, according to this method, the refrigerant temperature difference between the low-pressure section and the high-pressure section may be too large, and the degree of superheat on the low-pressure side may be too large. In this case, as a means for reducing the temperature difference between the low pressure side and the high pressure side, a decompressor may be provided between the condenser and the liquid receiver.

The decompressor reduces the pressure of the refrigerant that has passed through the condenser and is in a high-temperature and high-pressure liquid phase before being introduced into the receiver, thereby lowering the temperature of the high-temperature and high-pressure refrigerant, The temperature difference between the high-temperature refrigerant and the low-temperature refrigerant is reduced.

A temperature sensor is provided between the liquid receiver and the compressor to detect the temperature of the refrigerant returning to the compressor after heat exchange in the liquid receiver and to control the opening of the expansion valve. Is preferred.

[0013] In this case, the temperature of the refrigerant in a low-temperature, low-pressure superheated gas phase due to heat exchange in the liquid receiver is automatically detected by the temperature-sensitive sensor, whereby the opening of the expansion valve is determined. Under the control, the amount of the refrigerant circulating in the refrigeration apparatus is adjusted.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a refrigeration system (1) of the present invention, and FIG. 2 shows an enthalpy pressure curve of a refrigeration cycle when the refrigeration system is used.

The refrigerating apparatus (1) includes a compressor (11) and a condenser (1).
2), a liquid receiver (13), an expansion valve (14), and an evaporator (15). And, in the liquid receiver (13), the compressor (11) and the condenser (1
2), heat exchange between the low-temperature low-pressure refrigerant passing through the liquid receiver (13), the expansion valve (14), and the evaporator (15) in this order and the high-temperature high-pressure refrigerant in the liquid receiver (13). Heat exchange means (17) for returning the pressure to the compressor (11). Also, the receiver (13) and the compressor
(11), heat exchange in the receiver (13) and the compressor (11)
A temperature sensor (16) is provided for controlling the opening of the expansion valve (14) by detecting the temperature of the refrigerant returning to.

The liquid receiver (13) has a closed cylindrical shape, the top of which is connected to the outlet of the condenser (12). The liquid-phase refrigerant is extracted from the bottom of the liquid receiver (13), and the expansion valve (14) is opened. ). The heat exchange means (17) comprises a spiral heat exchange tube provided at the lower part in the liquid receiver (13), and the inlet of the heat exchange tube (17) and the outlet of the evaporator (15) have a low temperature. Low pressure refrigerant introduction pipe (18)
The outlet of the heat exchange pipe (17) and the inlet of the compressor (11) are connected by a low-temperature low-pressure refrigerant discharge pipe (19). The temperature sensor (16) is provided at an end of the low-temperature and low-pressure refrigerant discharge pipe (19) on the side of the liquid receiver (13).

The refrigeration cycle of the refrigeration system (1) will be described with reference to FIGS. A to I shown in FIGS. 1 and 2 correspond to each other.

The gas-phase refrigerant I is compressed by the compressor (11) to become a high-temperature and high-pressure gas-phase refrigerant A and sent to the condenser (12). The high-temperature and high-pressure gas-phase refrigerant B is cooled by running air or a fan in the condenser (12), and
And sent to the receiver (13). The high-temperature (about 50 ° C.) high-pressure liquid-phase refrigerant D is supplied from the outlet of the receiver (13) to the expansion valve (14).
Where the liquid refrigerant F expands rapidly and has a low temperature and low pressure.
Becomes Then, the refrigerant is introduced into the evaporator (15), where the refrigerant removes ambient heat and performs a cooling function to become a low-temperature (about 0 ° C.) low-pressure low-pressure gas-liquid mixed-phase refrigerant G. The refrigerant G that has passed through the evaporator (15) flows from the outlet of the evaporator (15) to the low-temperature low-pressure refrigerant introduction pipe (1).
It is introduced into the heat exchange pipe (17) by 8) and exchanges heat with the liquid-phase refrigerant stored in the lower part of the receiver (13) while passing through the heat exchange pipe (17). That is, the low-temperature and low-pressure gas-liquid mixed-phase refrigerant G that has passed through the evaporator 15 and the high-temperature and high-pressure liquid-phase refrigerant D that has passed through the condenser 12 (some of which may be in gas phase) undergo heat exchange. The low-temperature and low-pressure refrigerant G is heated to become a superheated gas-phase refrigerant H, and the high-temperature and high-pressure refrigerant D is cooled to become a supercooled liquid-phase refrigerant E. The superheated gas-phase refrigerant H passes through the low-temperature low-pressure refrigerant discharge pipe (19),
Is returned to the compressor (11). The high-temperature and high-pressure liquid-phase refrigerant D sent to the receiver (13) is not directly sent to the expansion valve (14), but is supercooled by the heat exchange in the receiver (13). After reaching E, it is sent to the expansion valve (14).

Therefore, the supercooling section DE is provided with the condenser (1
It is not in 2), but in the receiver (13).
H is not in the evaporator (15) but in the receiver (13). This eliminates the need for a conventionally required evaporator superheater and condenser supercooler, and the evaporator (15)
The deterioration of the cooling performance due to the presence of the superheated portion is eliminated, and the burden on the power side for maintaining the supercooled portion state in the condenser (12) is reduced.

The temperature of the superheated gas-phase refrigerant H is detected by a temperature sensor (16), and based on this temperature, the expansion valve (14)
Is controlled, and the amount of refrigerant circulating in the refrigeration system (1) is adjusted. Since the refrigerant G at the outlet of the evaporator (15) is not in the superheated gas phase, if the temperature-sensitive sensor (16) is provided at the outlet of the evaporator (15), the temperature of the refrigerant does not change, so the expansion valve (14) Although it is difficult to control the degree of opening of the refrigeration system, the temperature sensor (16) is provided in the low-temperature low-pressure refrigerant discharge pipe (19), so that the amount of circulating refrigerant is adjusted based on the temperature of the superheated part. The ability of each device to perform is maximized.

FIG. 3 shows a refrigeration apparatus (10) according to a second embodiment of the present invention, and FIG. 4 shows an enthalpy pressure curve of a refrigeration cycle when the refrigeration apparatus is used.

The refrigerating apparatus (10) of the second embodiment is different from that of the first embodiment in that a decompressor (21) is provided between a condenser (12) and a receiver (13). The only difference is that Other configurations are the same as those of the first embodiment, and the same reference numerals are given and the description is omitted.

The refrigeration cycle of the refrigeration system (10) will be described with reference to FIGS. A to J shown in FIGS. 3 and 4 correspond to each other.

The gas-phase refrigerant J is compressed by the compressor (11) to become a high-temperature and high-pressure gas-phase refrigerant A and sent to the condenser (12). The high-temperature and high-pressure gas-phase refrigerant B is cooled by running air or a fan in the condenser (12), and
And sent to the pressure reducer (21). High-temperature and high-pressure liquid-phase refrigerant D
The temperature is also reduced by the pressure decrease accompanying the passage through the pressure reducer (21), and the medium temperature (about 20 to 30 ° C.)
(12) Low temperature and low pressure compared to refrigerant C at outlet, but evaporator
(15) A gas-liquid mixed phase refrigerant E having a higher temperature and a higher pressure than the refrigerant H at the outlet is sent to the receiver (13). The medium-temperature and medium-pressure gas-liquid mixed-phase refrigerant E is sent from the outlet of the liquid receiver (13) to the expansion valve (14), where it is rapidly expanded to become a low-temperature and low-pressure liquid-phase refrigerant G. Then, the refrigerant is introduced into the evaporator (15), where it takes off the surrounding heat and performs a cooling action to become a low-temperature low-pressure gas-liquid mixed-phase refrigerant H. The refrigerant H that has passed through the evaporator (15)
(15) is introduced into the heat exchange pipe (17) by the low-temperature and low-pressure refrigerant introduction pipe (18) and passes through the heat exchange pipe (17).
3) Heat exchange with the liquid refrigerant stored in the lower part. That is, the low-temperature (about 0 ° C.) and low-pressure gas-liquid mixed-phase refrigerant H that has passed through the evaporator (15), passes through the condenser (12), and further passes through the depressurizer (21)
Heat exchanges with the liquid-phase refrigerant E, which is partially at gaseous phase at medium temperature and medium pressure, and the low-temperature low-pressure refrigerant H is heated and superheated gas-phase refrigerant I
Further, the medium-temperature medium-pressure refrigerant E is cooled and becomes all the liquid-phase medium-temperature medium-pressure refrigerant F. The superheated gas-phase refrigerant I is returned to the compressor (11) as a gas-phase refrigerant J through a low-temperature low-pressure refrigerant discharge pipe (19). The medium-temperature and medium-pressure gas-liquid mixed phase refrigerant E sent to the receiver (13) is not sent to the expansion valve (14) as it is, but is entirely exchanged by heat exchange in the receiver (13). Liquid phase refrigerant F
Then, it is sent to the expansion valve (14).

Therefore, the superheated section HI is connected to the evaporator (15).
Inside the receiver (13), which eliminates the need for a conventionally required evaporator superheated section, and reduces the cooling performance due to the presence of the superheated section in the evaporator (15). Is eliminated.

The temperature of the superheated gas-phase refrigerant I is detected by a temperature sensor (16), and based on this temperature, the expansion valve (14)
Is controlled, and the amount of refrigerant circulating in the refrigeration system (1) is adjusted. Since the refrigerant H at the outlet of the evaporator (15) is not in a superheated gas phase, if the temperature sensor (16) is provided at the outlet of the evaporator (15), it becomes difficult to control the opening of the expansion valve (14). Temperature sensor
By providing (16) in the low-temperature low-pressure refrigerant discharge pipe (19), the amount of circulating refrigerant is adjusted based on the temperature of the superheated section, and the refrigeration system
The capabilities of each device constituting (1) are maximized.

Also, by lowering the temperature of the high-temperature and high-pressure liquid-phase refrigerant D passing through the condenser (12) by the pressure reducer (21), the temperature difference between the low-temperature side and the high-temperature side becomes large, and the expansion valve The refrigeration system (10), which prevents the problem of the control width becoming too large and slightly reduces the temperature efficiency, but has excellent control responsiveness
Is obtained.

[0029]

According to the refrigerating apparatus of the present invention, it is not necessary to provide the superheated portion of the evaporator and the supercooled portion of the condenser, which are required in the past, so that the cooling performance due to the presence of the superheated portion in the evaporator is eliminated. The drop is eliminated, and the load on the power side for maintaining the supercooling unit state in the condenser is reduced. As a result, a refrigeration apparatus having an improved coefficient of performance without significantly changing the conventional refrigeration apparatus can be obtained.

In the case where a decompressor is provided between the condenser and the liquid receiver, the temperature difference between the low-temperature refrigerant and the high-temperature refrigerant becomes small, the control by the expansion valve becomes easy, and the control response is improved. I do.

In the case where a temperature sensor for controlling the opening of the expansion valve is provided between the liquid receiver and the compressor, the opening of the expansion valve is controlled on the basis of the temperature of the superheated portion, so that the refrigeration is performed. The amount of the refrigerant circulating in the apparatus is adjusted, and the performance of each device constituting the refrigeration apparatus is maximized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a refrigeration apparatus according to the present invention.

FIG. 2 is a diagram showing an enthalpy pressure curve of the refrigeration cycle of the first embodiment.

FIG. 3 is a block diagram showing a refrigeration apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating an enthalpy pressure curve of a refrigeration cycle according to a second embodiment.

FIG. 5 is a diagram showing an enthalpy pressure curve of a conventional refrigeration cycle.

[Explanation of symbols]

 (1) (10) Refrigeration unit (11) Compressor (12) Condenser (13) Liquid receiver (14) Expansion valve (15) Evaporator (16) Temperature sensor (17) Heat exchange tube (heat exchange means) (21) Pressure reducer

Claims (3)

[Claims] 1. A compressor (11), a condenser (12), a receiver (13),
In a refrigerating apparatus provided with an expansion valve (14) and an evaporator (15), a compressor (11), a condenser (12), a receiver (13), an expansion valve (1).
4) and the heat exchange means (17) for exchanging heat between the low-temperature and low-pressure refrigerant passing through the evaporator (15) and the high-temperature and high-pressure refrigerant in the receiver (13) and returning the low-temperature and low-pressure refrigerant to the compressor (11). ) Is provided in the liquid receiver (13). 2. The refrigerating apparatus according to claim 1, wherein a pressure reducer (21) is provided between the condenser (12) and the liquid receiver (13). 3. An expansion valve for detecting the temperature of a refrigerant that returns heat to the compressor (11) by exchanging heat in the receiver (13) between the receiver (13) and the compressor (11). 3. The refrigeration system according to claim 1, further comprising a temperature sensor (16) for controlling the opening of (14).